Electron spin resonance, other biophysical, and biochemicalmethods are being used to study erythrocyte membranes from patients with Huntington's disease (HD). Changes in the physical state of membrane proteins and several morphological, enzymatic and mechanical properties of HD erythrocytes membranes have been observed. Research in the future is aimed at delineating in more detail the molecular basis for these observations. Greater insight into this neurological disorder is evisioned.